Benefaction
by The Third Marauder
Summary: Loki steals the International Prototype Kilogram. The Avengers try to get it back. It doesn't quite go the way anyone expects. (Companion to Proprietary and Appropriation)
1. Benefaction

**Disclaimer: All of the Avengers belong to Marvel Comics. **

**Note: This can be seen as an episode between Proprietary and Appropriation, or read independently. **

**...**

**...**

**...**

* * *

He wakes up to the sound of the Avengers Alarm.

"JARVIS?" he slurs, hand searching the bedside table to grab the clock. A green 3:42am blinks back at him.

"Sir, there appears to be a Loki related incident. Agents Barton and Romanov are receiving the briefing now."

Bruce takes his time getting dressed. JARVIS would have told him if it was urgent, and it's usually better to give Clint time to calm down before trying to make any plans when it comes to the demigod.

He must not have given it enough time, though, because he can hear Clint's shouting as he pads over to the common area.

"—woken up at ungodly hours over a tin can!"

"It's the International Prototype Kilogram!" And that's Tony's voice. Bruce can hear the outrage.

"A tin with a fancy name. Maybe you could get Warhol to paint it."

"It's not tin," Bruce corrects mildly as he enter. Tony spins around, relief pouring over his face. "It's primarily made of a platinum alloy."

"Some iridium."

"Only about 10%," he dismisses Tony's correction.

"Finally! Someone who speaks English."

Steve groans from the corner, face buried in his hands.

"There's footage of Loki near the Pavillon de Breteuil in Saint Cloud, France." Natasha explains, "It seems he's stolen the IPK."

"They have copies there," Bruce turns to Tony for confirmation.

"Six sister copies and ten working ones."

"There is concern he might have tampered with those," Natasha continues as if there was no interruption.

"Concern?"

"He drew a green smiley face on one of them," Steve supplies through his hands.

Bruce bites back his laugh. "I suppose we're heading over, then."

"Just waiting on you, Jolly Green," Tony claps him on the shoulder.

* * *

They make a side stop into the city before completely heading out. Most countries have their own working copies of the IPK, they just need to get one so they can recalibrate the original.

Tony spends the flight over on the phone with administrators from the Pavillon. Not that Bruce can understand any of it, since the billionaire speaks with them in fluent, unaccented French. He can tell this lack of information is specifically weighing on Cap.

"Show off," he mouths when his friend finally looks up. He gets a blinding smile and a wink in response.

By the volume of Steve's grinding teeth, he isn't the only one who feels relieved when Tony finally puts the tablet down.

"One of the scientists noticed it missing this morning," he announces, throwing up the security video. "They took a couple hours to go through the tapes, last they saw it was from a video sweep at around 2am GST." He pauses the playback.

"Guess no one thought having continuous feed over a rock was overly important." Clint snorts from the pilot seat

"And Loki?" Steve says quickly before Tony can get started again.

"Nothing on the building cameras. But CCTV noticed him in the area yesterday morning." Natasha replies. "You're not the only who understands French," she says to Tony's scowl.

* * *

"We've got a problem," Clint announces about an hour out from landing.

Bruce pulls himself away from his reading.

"They just opened the case for the copy from London. Looks like Loki got to it, too."

"Looks like?" Steve asks.

"See for yourself."

The image of the London kilogram is thrown up in the hold.

"Is that—"

"I think it's his caricature of the queen," Clint critiques drily.

Tony tilts his head, observing it at an angle. "Or a dirty version of – _hey_!"

"But they checked it before they sent it over," Steve dodges Tony's attempt to throw his projectile back at him. "It was fine then."

"Maybe some kind of delayed manifestation spell?" Bruce suggests. "It's definitely his though."

Nobody doubts that. Eight months ago, a up-and-coming super villain had attempted to share in the deep green color scheme that was Loki's calling card and paraded about Italy in a sartorial display of elegance. He was dropped off to Interpol two weeks later, his costume changed to an equally magnificent shade of purple. _To match his bruises_, the note Loki had left with him said in green ink. The color had been left thoroughly alone since then.

"Ours is still ok," Natasha's words are cautious though, as she rotates the container, inspecting the block. "No green anywhere."

Bruce looks at Tony. "We should probably ask them to get a couple more."

"Holland and Spain. Perhaps Germany, too," Tony agrees, tossing a phone to Steve and dialing on another "Just for comparison. There's over a hundred working copies, he couldn't have gotten to all of them."

* * *

So it turns out Loki _could_ tamper with the rest of the world's copies of the IPK.

"It's only 40 grams," Steve looks confused by all the dismayed looks and, _well_, science.

"_Only_!"

Bruce ignores the strangled yelp from one of the scientists behind him and instead speaks to Tony. "You're sure you zeroed it properly right?"

Tony's glare is murderous as he mutters something about where Bruce can shove his seven PhDs. From the wince on one of the scientist's face it was not somewhere pleasant.

They're standing in a large lab in the Pavillon de Breteuil, three copies of the IPK scattered across a table also holding a small scientific scale. All of them different weights across a 40g spectrum.

"We have time," Tony keeps his voice low. "A couple days before this becomes emergent."

Bruce nods. "Most companies use digital scales. As long as nothing throws of the electrical current, they should still be roughly calibrated – enough so that it shouldn't affect too much."

"You're talking like world trade is at stake." Clint interrupts, disbelieving. At Tony and Bruce's lack of opposition, he looks aghast. "You mean to say that we've tied the global economy _to a block_."

"It's the International Prototype Kilogram!" A chorus of voices join Tony's objection.

Bruce pinches the bridge of his nose. "Anyway, it's not just the economy. We're talking manufacturing, engineering, the safety of planes, trains—" he breaks off as his earlier words hit him.

Natasha is a moment ahead of him in the realization, because she's already sprinting to the door, shouting back "_Strange_!"

* * *

A few days ago there had been a message from Earth's Master of Mystical Arts saying that his colleagues had identified a mysterious magical electromagnetical pulse hours earlier. It had been short in duration and with no clear source or serious aftereffects. Given that, the Avengers hadn't felt the need to follow up.

"Banner – oh, no, it's all of you," the doctor – _real_ doctor, as the wizard was so fond of reminding – grimaces. "To what do I owe this pleasure."

As a rule, Bruce kept conversations with Stephen Strange short. He liked Tony, truly the billionaire was his best friend, but one overly arrogant superhero with a goatee was enough.

"That magical pulse from Thursday," Bruce gets to the point immediately. "Were you able to discover anything else about it?"

Strange sneers. "I thought you had dismissed it as unimportant?"

"We might have been incorrect," Steve takes over, before anyone could be needled. "Please, we could use your help."

"As I told you, it was a magical electromagnetic pulse. Designed to impact a very specific type of technology. Given the lack of widespread distress it either didn't work or had some kind of delayed trigger."

They all share a worried look.

"What?" Strange is quick on the pick up. "What's going on?"

"Would you be able to tell if the spell worked?" Bruce asks. He can hear the gears turning in Tony's head, just as they are turning in his. "Or what machinery it was directed to."

The sorcerer shakes his head. "It was very sophisticated work. No magical signature and no real way for us to trace it. Given the level of skill that in itself requires, I have a hard time believing it isn't doing what it was meant to."

"Thank you, Doctor," Steve says gratefully, although he is wearing the same blank look he gets whenever anyone talks about science. "We think Loki may be behind this, if you and your partners could—"

"We'll dig up whatever we can find."

* * *

As soon as the call is over, Natasha turns to Bruce.

"He went for the scales?"

"Has to be."

"Only thing that makes sense," Tony concurs. "We still have time to handle this. A couple days before it turns into a real problem."

"You keep saying that. What exactly do you expect to happen?"

Bruce begins his explanation. "The IPK is the base unit of mass used around the world –"

"Not in America," Natasha chimes.

Tony rolls his eyes, "Actually the pound is now defined in term of the kilogram, but yes, _we get it_, the imperial system is ridiculous."

"_Anyway_," Bruce continues, "the IPK is used as the standard for virtually units of mass on the planet. It is how we defined weights. So if I'm the U.S. trying to sell 20lbs of steel to Canada but their scales only measure it as, say, 19lbs, then they're not going to want to pay us as much. Expand that to the whole word."

"And not just trade," Tony adds, "think of how many precisely measured pieces goes into everything we use on a daily basis – cars, planes, kitchen supplies."

The severity of the situation seems to finally dawn on Steve.

"You said we had time?"

"It'll take several days for companies to pick up on weight differences in their products," Clint says thoughtfully. "Could you build a replacement?"

Bruce takes a second to ponder but Natasha is already shooting down the idea. "Loki would just steal that too. We need to find something more permanent."

"No, we need to make sure people don't start panicking and crash the stock market first," Steve corrects, as somber as anyone who lived through the Great Depression ought to be.

"We should have the council spread the information to select people – world leaders, etc." Tony affirms, "The longer we can keep the public from discovering this, the better."

* * *

Which would have been a fine plan had Loki not decided to appear at Capitol Hill and announce his theft to the entire Senate chamber.

SHIELD doesn't even pick on the disruption right away. For all their spying, no one had ever thought to put serious effort on monitoring CSPAN, so if the Avengers hadn't already been in DC meeting with the Pentagon when the channel went dark, the demigod might have been long gone.

Tony and Natasha go in first with Clint separating to look for a good vantage point. Cap had initially protested until Tony had reminded them that of the group Loki seemed to like him best and would not kill Natasha without Clint present.

Knowing Tony was Loki's favorite still doesn't prepare any of them for the relieved welcome he gets. "Thank the Norns you've arrived, Stark."

"I, uh, you're welcome?"

The prince grabs Tony's armored arm and pulls him to the rostrum, seemingly not even noticing Natasha slip in through the side entrance. Through Tony's suit cam they can see many of the senators hiding behind their desks, and besides a couple security guards unconscious by the doors, no one seems to be too injured.

"Why isn't he panicking?" Loki demands. The president pro tempore whimpers, quivering behind the podium.

"_He hasn't killed anyone_," Natasha whisper comes through the coms at the same time._ "Tony keep distracting him_."

"_Distract him from _what?!" Tony hisses back, before projecting out a baffled reply to Loki. "He looks sufficiently panicked to me."

"This? He scoffs, disdainfully lifting the diaphoretic senator by his collar. The man's legs flail under him "This is a selfish fear. Your spider could tell you the same, if she wasn't so busy trying to save these mindless twits."

There's a sharp inhale on the coms, from Clint, Bruce thinks, and they can hear the telltale hum of the Iron Man thrusters warming up.

Loki holds his hands up in the air, a universal sign for ceasefire. "These petty humans are all of them beneath me. You may have them back as soon as you explain why _no one is properly panicking_."

"Loki," Natasha calls from offscreen, "they're all terrified you're going to kill them. What reaction are you looking for?"

He gapes at them. "You truly don't… _The IPK_. I have stolen your kilogram, the very basis of your trade, and interrupted your government proceedings to pronounce it to the entire world," he gestures to the what Bruce suspects is a video camera. "Yet look!" He shoves a phone into the Avenger's face.

An iPhone, Bruce notes absently. That is probably vexing Tony. The screen is a little blurry through the suit camera, but Bruce can still clearly see the stock market app with the DOW flashing. It's positive for the day.

"_He's trying to crash the economy. _" Definitely Clint's voice this time. _"But nobody watches CSPAN and most people wouldn't know what the IPK is anyway—"_

"—_and politicians are idiots," _Tony finishes, a hint of glee to his tone.

"Anything now?" Loki presses hopefully, peering down at the president pro tempore who had been attempting to scramble away.

"I'm sorry," the man cries, "I don't know what this IPK is."

Loki rounds on Tony, his expression one of utter disgust.

"The public school system is truly a travesty," Tony says gravely. Bruce can hear the suppressed amusement.

"_Tony, don't—" _

"We should probably elect someone to fix that."

The captain sighs, "_provoke him._"

* * *

Loki stabs Tony before he disappears, but it's a half hearted thing, barely breaking through the slit in his armor and the skin underneath.

"I think I'm growing on him," Tony says cheerfully while Bruce closes the wound.

"You know, we still need to find a solution for this whole mass problem."

Tony pouts. "All work and no play makes Bruce a – _ow, come on_."

Bruce hides his smile as he finishes the last suture.

* * *

For all Tony's mocking, they do end up in the lab that night debating possible solutions. The rest of the Avengers stop in occasionally to see if there is progress, but for the most part, the discussion is still incredibly theoretical.

They are in the middle of a calculation, when JARVIS directs their attention to the screen.

Loki is back on CSPAN. He seems to be using a large knife as a pointer for the multiple charts floating in the air.

"What the—"

Tony is interrupted by Steve's breathless arrival to the lab. Clint and Natasha slide in after him.

"_Did you see_—?" Steve stops once he notices it's on the screen.

They all watch attentively as Loki explains the inelegance of defining mass by an amount of volume. And it dawns on Bruce.

"He's giving a science lesson," he breaths. They gawp at the television.

It takes a few minutes and Loki throwing a knife at one of the senators for incorrectly answering a question, but Steve finally halfheartedly suggests, "Guys, we had better go."

"It might be better if we don't?"

"_Tony._"

"I'm just saying, it would be for the good of education everywhere," but the billionaire is getting up.

* * *

They're on the Quinjet when Natasha asks, "how do you think he got the charts?"

The thought of Loki terrifying a Kinkos employee into formatting his visual supplements pushes them all to laughter.

* * *

They all go in this time. Whatever Loki's scheme he has made no play for true violence, and they don't think he would feel threatened by their group appearance.

He isn't.

"Finally," he snaps when they arrive. "Your leaders are inept imbeciles. It is beyond me why you work so hard to protect them."

"Me too," Clint mumbles and then responds to the disapproving look Natasha throws his way. "What, you know you agree with him."

"_Not the time,_" she hisses back.

"If you wish, I could kill the particularly stupid ones. Allow you to replace them with more worthy candidates," Loki offers magnanimously. The thought seems to cheer him up and he twirls a newly conjured knife.

"There unfortunately aren't any," Tony answers at the same time Cap growls, "No!"

Cap glares at them all and emphasizes slowly, "You won't harm them."

Bruce hears the sighs of relief from the senators to his left.

There is a gleam to Loki's eye as he prowls towards Steve. "Ever the noble captain. You proudly wear the flag of your people, yet you allow your leaders to be illiterate buffoons, ruining your nation with petty squabbles. What do you work so hard to defend?"

"Our ideals," Steve doesn't even hesitate.

"Ideals of ignorance?"

"Of a republic built on freedom, equality and justice."

"Regimes fall every day," Loki says offhandedly. Bruce wonders why that makes Natasha flinch.

"Loki," Clint steps up, arrow knocked. "We want the IPK back."

For the first time there is a flash of anger on Loki's visage. "Threaten me again, and I will kill every last one of them, _I do so swear_."

In a flash, Tony's mask has popped back on, his arms up, and Cap has his shield in hand. The air is tense for a few seconds, and then Loki relaxes into a smile. It's a sharp thing that makes the hair on the back of Bruce's neck stand up.

"I had thought to bring glad tidings of a world made civilized. No matter," He turns to the camera. "Look to your heroes, people. Let them be your example."

He disappears.

* * *

Bruce slowly lets out the breath he was holding.

Loki's stunt seems to have gotten him the attention he sought, although the mainstream media seemed to be focused more on his philosophical debate of the qualities of leadership than his theft of the IPK. Still, it was enough to worry the World Council, and they spent the ride home in conference with them.

"Get it back," Clint sneers, putting more force than necessary into flipping one of the switches to prepare for their descent. "What do they think we've been doing this whole time?!"

Natasha puts a calming hand on his shoulder. She turns to Bruce. "Are we any closer to finding a more permanent solution?"

He shakes his head. "We agree that the best way to avoid this is to define the kilogram based on natural constants, but it'll take time to figure out how."

"That has to be our top priority," she says firmly. "The rest of us will –"

"Nat," Clint interrupts, pointing out the cockpit window.

Thor is waiting for them on the tarmac.

* * *

It takes them more time to convince Thor of the severity of the situation than it should, considering the demigod should be the last person to doubt the impact a small stone-like object might have.

"Loki has oft stolen small trinkets from others. There was this time with Idunn's apples…" he reminisces affectionately. "He has always been fond of his tricks."

"This is more than a trick, Thor. There are serious consequences to this." Steve explains evenly.

Thor's brow furrows. "You said it wasn't magical?"

"It's isn't, but—"

The god of thunder waves a dismissive hand. "My brother isthe god of mischief. As soon as he's satisfied with the amount of chaos he's caused, he'll return what he took, he always does."

Natasha, Bruce and Steve all protest at once, their words incomprehensible over each other's.

The emphatic nature of their response makes Thor suspicious. "You're _sure _the stone is not magical?"

"It's not a –" Tony snaps before sighing and massaging his temples. "Look it's a _very _important _nonmagical_ stone. And we _really_ need it back."

The Asgardian looks unconvinced, but he shrugs, "Very well, I shall help you retrieve your object."

Bruce knows he's not the only one to hear Thor mumble under his breath, "you humans are so petty."

* * *

Tony and Bruce spend the next day in the lab while the rest of the Avengers attempt to track Loki. Which proves less difficult than they imagined, since the prince seems to be taking a world tour of legislative chambers to announce his grand theft.

The others catch up to him in Ottawa. JARVIS plays the video.

"Loki, return to the humans their rock," Thor is commanding, hammer positioned threateningly.

"_Rock_," Loki shrieks. "It's the International Prototype Kilogram, you clot." He glowers at the rest of them. "Surely Banner and Stark would not have left you so oblivious."

Bruce turns, "I think that was a—"

"Definitely a compliment," Tony crows gleefully, eyes fixed on the screen.

"And how did _you_ come by such Earth knowledge, Loki?" Thor questions suspiciously.

"It was on google." At Thor's blank look, Loki huffs, throwing his hands into the air. "I read it – honestly, what are you planning to do once you are king?"

"What need have I for reading when I might have you by my side, brother?" Thor responds brightly. It sounds like an exchange they've had multiple times before.

"Truly, it would serve Asgard right to have your inanity on the throne – Thor, you great oaf."

The elder Asgardian, seemingly thinking Loki's diatribe had him distracted had thrown himself forward in an attempt to tackle his wayward brother… and passed straight through.

"Are you seriously ever not going to —" Cap's shield sends the real Loki flying, straight into one of the Canadian MPs.

"I'm so sorry," the MP cries, trying to scramble to his feet. "Are you ok?"

Loki, who is already back up and pulling out the arrow Clint had simultaneously shot into his shoulder out stares at the Canadian politician, completely perplexed. The man, to his credit, looks entirely earnest.

"Oh, god, _Canadians_," Tony groans next to Bruce.

The prime minister seems to have the same idea. "Just like Americans," she looks disapprovingly, "to resort to violent brutality."

Steve is defensive, "Ma'am, we were protecting you–"

"From a lecture?" She raises her eyebrow. She turns to the still bewildered Loki. "While we'd prefer you to bring such complaints through proper channels next time, thank you for exposing the holes in our education. Let's go to my office and discuss this further."

Loki allows himself to get ushered out.

"What the _hell_ just happened?" Clint demands over the coms.

* * *

"Do you think he does it on purpose?"

"What do you mean?"

He and Tony are sitting in the lab, watching the UK become the latest country to approve funding for revamping their science education. Ever since Loki had stabbed one of the South African National Parliament members for daring to suggest that money might be better allocated to non-educational spending, many countries (still not the U.S. Bruce notes irritably) had begun to introduce new funding measures.

"Well his last few schemes have been decidedly less _evil_ than his usual rule the world, destroy his enemies thing."

"The plan with the cobalt in the Congo–"

"Ended up exposing an evil dictator and increasing access to those natural resources for the entire continent," Bruce points out.

"And now he's ensuring that the next generation won't be idiots." Tony ponders the implication of Bruce's theory. And then he groans. "They are such _children_."

Bruce looks at him quizzically.

"Earth is under Thor's protection, he proclaimed it to the galaxy when he fought the Chitauri. Except Earth is weak."

"So he's using his plots to bolster the planet," Bruce realizes. "Because he's too stubborn to directly be seen as helping Thor—"

"_Immature_ _children_," Tony confirms.

* * *

JARVIS is streaming parliamentary proceedings from Kenya on the lab flat screen when Steve pokes his head in, blue eyes hopeful. "Any breakthroughs?"

Bruce hides the window on his Starkpad.

"Nope," Tony says quickly.

The blond looks disappointed and heads back.

"Do you think we should—?"

Tony makes a strangled sound and points emphatically at the TV. "27 countries and counting," he reminds.

Knowing they're doing the right thing does not entirely dispel Bruce's guilt over lying. So, he resolutely does not look at the darkened screen in the corner displaying the new fundamental definition of Planck's constant before reopening the window with Galaga on it. He's only a handful of rounds from beating Tony's high score, anyway.

* * *

Investors apparently have no interest in the betterment of global education, because the markets finally start to get antsy. The World Council call in an apoplexy demanding they step up their search for the IPK, and so Bruce and Tony are dragged away from the lab to rejoin the team.

"Do you think if we asked, Loki would kill the world council?" Clint has a murderous glint when the call ends.

"We'd have to find him first." Tony's response is cavalier until he catches Steve's disapproving eye and walks the words back.

His sentiment is not incorrect, though. Loki had not been seen in the few days after he stabbed the South African MP.

Natasha, meanwhile, watches Bruce thoughtfully. It takes him a couple seconds to recognize her idea.

"No, let's not."

"He might be able to help." Her words hang in the air, tempting.

Bruce can see by the resolve in Steve's face, that he's already lost the battle. "Jarvis," he sighs, "call up the good doctor for us."

* * *

It's like pulling teeth getting Dr. Strange to help, but eventually they have a location.

"What's in Minneapolis?" Clint is taken aback.

"Maybe he wanted to visit the Mall of America," Strange answers sarcastically. "I'm not a mind reader."

"Thank you, Dr. Strange," Bruce cuts in. "I'm sure we'll be able to take it from here. As always, your help is appreciated."

The magician sniffs, but in the end does offer a stiff farewell and a promise to update them if he discovers anything else.

"It's a big city," Steve assesses the map Tony's just thrown onto the screen, "I don't see how we could narrow down the search area to a reasonable size."

Which is where they would have been stuck had Thor not casually supplied, "Most likely he would be near his apartment."

They all stare at the prince. "Apartment?!"

"Aye, he's made a lovely home there. His neighbors are very friendly. Lucy Berg's cookies are even better than pop tarts!"

"Thor," Natasha words carefully while the rest of them get over the fact that Loki has an apartment in Minnesota, "you've been to his home? You know where it is?"

The thunder god nods. "He has, on occasion, had me watch his cat when he was busy with his mischief."

Tony's expression is an odd mix of disbelief and suppressed laughter.

Thor meanwhile seems to have processed their intent, because suddenly he continues forcefully, "Oh no. I know what you are thinking, but my brother would never forgive such treachery—"

Natasha steps forward, eyes gleaming.

* * *

Thor sulks the entire journey to the twin cities. They land in a basketball court two blocks away.

"We need a plan of attack. _Don't_ _say it_," Steve snaps at Tony before he can get a word in.

"It worked last time," Tony grumbles, but he does listen.

"We could just ask him," Bruce suggests.

Clint scoffs, "Hey, let's just ask him to stop trying to destroy the world. Wonder why we've never thought of that before."

Bruce feels a flicker of annoyance at the dismissal. Steve responds before he can. "It isn't the worst idea. He's been uncharacteristically diplomatic about this whole thing."

"He's killed a dozen people."

"Which isn't –" Steve's face flushes. "I hate that I was about to say that."

They hammer out a generally strategy (as well as an escape plan for Bruce in case things go south) which Bruce just knows is going to fall to pieces anyway.

"Thor?" Steve asks the sullen Asgardian gently, "Anything you want to add?"

At first his lips are set into a stubborn line. But then his face brightens a little, "I know how to get us past the doorman. Loki and I used to do this maneuver called 'Get Help'—"

Steve is actually listening intently. Bruce sees Natasha roll her eyes and prepare herself to explain that a doorman would never bar the avengers from entering a building when a banging on the Quinjet takes them all of guard.

They look to Tony who is pulling up the outer security feed.

"Are you quite done?" Loki's bright green eyes blink back at them as his words filter through the camera microphones.

Clint swears.

* * *

Loki takes no time to settle into the Quinjet once they allow up him. "I have been waiting for _thirty minutes_."

There is a pause as they all figure out how they should respond.

Steve clears his throat, "Loki, we've come for the I.P—"

"Brother, I am truly sorry for revealing -" Thor's outburst is silenced with a wave of Loki's hand.

"Do shut up, Thor. Had your wizard been less inept my magical trace would have led you right here, so, as it happens, your actions have saved me quite a bit of effort."

"You mean—"

Loki waves his hand again and Clint's jaw clicks shut. "I don't recall you being this keen on repeating the bloody obvious when you were under my thrall."

The rest of them assume fighting positions.

"For the love of - surely you don't mean to release the beast in one of your civilian cities?!" Loki exclaims. He releases the magic on Clint and Thor, and shows his hands in the universal gesture of innocence. "I have summoned you here to return your precious IPK."

They all gape at him.

"It appears that humanity is by and large too mindless to succumb to such intricate ploys. I shall have to lower myself to more brutish strategies, and so this game no longer serves any purpose." He continues loftily. "By and by, it becomes increasingly clear to me your fondness for this backwater realm, brother. For the first time in your life, you must feel somewhat intelligent."

He pulls the IPK out of an interdimensional pocket, offering it.

"Just like that?" Natasha's doubt is evident.

Loki is thoughtful. "Well I do have one condition."

"_Knew it_," Clint mutters and knocks an arrow. Steve grabs his arm to prevent him from firing. Loki graciously pretends to not notice any of it.

"Jörmungandr will be disappointed to have his favorite toy taken away. You will offer a suitable replacement."

"I will search the nine realms for a worthy gift, you have my word," Thor swears.

Privately Bruce thinks Thor is foolish to pin his hope for mending their fraternal relationship on the cat named after the creature mythologically destined to kill him. Then again, perhaps the passing look of affection on Loki's face at Thor's offer shows that Bruce doesn't know what he's talking about.

Loki grins, and hands the kilogram to Tony.

* * *

The Council's gratitude for the safe return of the IPK lasts all of two seconds before they're demanding he and Tony find an alternate solution for the definition of mass that can't be stolen.

They had originally planned to wait two weeks before revealing their proposal defining the kilogram based on a now fundamental value of the Planck's constant, but Clint corners them days after returning the IPK.

"Just give them what you've developed, already. I'm tired of Cap lecturing me that you have more important things to work on than my exploding arrows."

Bruce looks at Tony. The billionaire shakes his head slightly to say it wasn't him.

The archer, of course, marks the exchange. "You invented a new element in 48 hours. It doesn't take a master spy to know that there's no way you haven't had a solution for at least a week."

Tony side-eyes Bruce. He gives a quirk of his eyebrow as if to say _might as well_.

The inventor grins and slings an arm over Clint's shoulder. "Fine, but you get to explain to Pepper why I'm not working on the clean energy propulsion tech for Stark Industries."

* * *

The scientific community is appropriately awed by their idea to define the kilogram by invariable natural constants. Tony makes Bruce take first authorship of the resulting proposal and then drags him to the General Conference on Weights and Measurements.

He tries to get Steve to come as well, but the soldier, perhaps sensing that Tony only wanted him there to see him overwhelmed by the science of it all, intelligently refuses.

"But _how_ did you come to this value of Planck's constant?" Bruce is being peppered by questions after his presentation regarding the development of their new classification.

A couple people try to monopolize Tony, but he redirects them with variations of, "You'll have to ask Dr. Banner, Professor, he was the brains of the operation."

Bruce tries to catch Tony's eye the third time he does that, but for once the billionaire is hanging in the corner, staying well out of the spotlight.

He finally escapes the gaggle when the next big presentation is announced and joins Tony at his table.

"We came up with the constant together," he reprimands softly.

Tony looks at him over the top of his sunglasses. "You have seven PhDs. You're the smartest man I know, and I am _sick and_ _tired_ of people thinking your only importance is as the Hulk." He pushes the sunglasses up.

Bruce doesn't push the topic any further. But there is a warmth in his chest for the rest of the conference.

* * *

Everything dies down and the world goes back to normal.

"It's a shame, really," He comments weeks later while they're fiddling in the lab. "For all his sociopathic tendencies, Loki was an extremely effective teacher."

Tony shrugs. "Well, if he ever gets tired of world domination, maybe you could suggest it to him? Even maniacal gods must go through midlife crises, right?"

Bruce laughs at the absurdity of it and returns to his work.

* * *

**Fin**

**...**

**Author's Note:**

_I happened to read an article about the retirement of the IPK about a year ago, and was immediately struck by this insane idea of what would have happened had someone stolen it when it was active. And so this story was born. __The anticipation of Avengers: Endgame gave a lot of motivation to play with my favorite characters before some of them are, maybe, retired for good, and I'm very pleased I was able to polish this up before the movie comes out.  
_

_I'm not intending to write different stories in this series from multiple character's POVs but they just seem to get written better this way. I think it's easier to convey Loki's ambiguity when not writing from the inside of his mind because we all have to guess what he's thinking. At the same time, Bruce's keen observation seemed like the perfect lens to ponder over all the different characters' motivations. _

_Hope you all enjoyed this glimpse into the events between Proprietary and Appropriation! Thanks for reading, and, as always, feedback of any kind is always appreciated. _

TTM


	2. Series Timeline

I've been asked by some to make a story timeline/order for this "series" now that the stories are no longer sequential.

**2012** **Avengers/Battle of New York**

**2014 Proprietary**

**late 2016 Benefaction**

**early 2017 Appropriation**

**2022 In Loco Parentis **

I will add other stories if and when they are written and published. Thank you for reading so far!

**~TTM**


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